Sandarbh - Issue 80 (March-April 2012)

Table Of Contents

1. Testing For Starch In Plants – My Experience by Jyoti Milind Medpilwar [Hindi PDF, 388 kB]                        
   In Issue 78, we had carried an article by a teacher describing the problems in an experiment to test for the presence of starch in leaves.  In this article, another teacher shares her experiences doing the same experiment. She too tries variations of the technique given in the textbook when she encounters problems. However, she has different outcomes.
   
   
2. Atomic Weight: Changing Standards And Some Interesting Events From The Past by Sushil Joshi [Hindi PDF, 312 kB]                                              
   Till the early 20^th century, the methods to calculate the atomic weights were chemical, and the standards for atomic weight were Hydrogen and Oxygen atoms. One of the assumptions that the chemists had made was that isotopes were stable. When physicists challenged this chemists were confounded.  Read here about how finally the atomic weight was defined and standardized.
   
   
3. Has The Kilogram Become A Little Lighter Or A Little Heavier? by Vinatha Viswanathan Translated by Ambrish Soni [Hindi PDF, 234 kB] [English PDF, 22 kB]
   A few decades ago, guardians of the only physical reference for the kilogram in Paris found, to their dismay, that there had been a change in its mass. Any change in this reference mass instantly renders kilograms all over the world, wrong. The quest for a universal, accurate, unchanging reference for this important measure of mass intensified, and is finally nearing its goal.
   
   
4. Learning Independent Writing Along With Mathematical Units by Varsha Ladge Translated from Marathi by Madhav Kelkar [Hindi PDF, 78 kB]
   A teacher greets her six-standard students on their return from their summer vacations by asking them to write an essay on their break while including at least five mathematical units in them.  The children respond enthusiastically and the exercise forces them to relate mathematical units to their daily lives in an unconventional format for a maths class - essays.
   
   
5. Education And Children’s Literature by Krishna Kumar Transcribed by Dhuleshwar Rawat [Hindi PDF, 137 kB]                                                       
   This is the first of a two-part series of a talk given at an occasion to celebrate the 300thissue of Chakmak, a children’s magazine published by Eklavya.
   A prolific writer, commentator and teacher in the field of education, Professor Krishna Kumar speaks about the place of children’s literature in the current education system and social fabric of our country. Read in this section some of the history of children’s literature and how assumed importance over the decades.
   
   
6. Why Can’t We See Sound Or Hear Light? Sawaliram Answered by Sushil Joshi Translated by Parul Soni [Hindi PDF, 64 kB] [English PDF, 70 kB]                                     
   Alyina, a 13-year old from Al Qamar School, Chennai sent in this question. Our sense receptors are organized so we can normally only see colour and hear sound. Interestingly, it is possible to see sound and hear colour. To know how this happens, read on...
   
   
7. Turning A New Leaf – Part 1 An interview with H.Y. Mohan Ram by Sujata Vardarajan Translated by Manohar Notani [Hindi PDF, 337 kB] [English PDF, 7.7 MB]
   The first of a two-part series. A renowned scientist reminisces about his life and works: the research questions he tackled, his students, mentors.
   In this part read about this Professor Mohan Ram’s childhood, his early influences, how his interest in botany developed and how he came to research plants. He talks about his journey from Mysore, where he did his schooling, to Cornell where he went for his post-doctoral work and the people he met and worked with along the way.
   
   
8. Tannins As Plant Defence by Kishore Powar [Hindi PDF, 188 kB]
   We know of tannins as chemicals used in the production of leather from animal skins. Tannins however have a very important role to play in the natural world as chemicals that defend plants from herbivory. Read here about how plants defend themselves against insect predators and how the predators overcome these defenses.
   
   
9. May You Grow Up To Be… by Rinchin Translated by Sushil Joshi [Hindi PDF, 226 kB]
   A gifted storyteller, young Shankar's tales and anecdotes are such fun to listen to, full of imagination and wit. Read here how Shankar narrates the story about a village whose inhabitants have mysteriously disappeared. Sabari, who feels that Shankar's stories must not be lost, captures them with her breath and stores them away safely with the others in a little box buried under a tree.
   
   
10. Termites – Amazing Architects by Parul Soni [Hindi PDF, 242 kB]
    The African termite is famous for the gigantic mounds it constructs in African savannas. The mounds are an intricate network of galleries and chambers designed to maintain internal temperatures within a narrow range. The article describes both how and why these animals are such amazing architects.

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